DOS filenames are all uppercase when viewed from the SCO OpenServer system, and are restricted to eight letters, followed by a period, then a three letter extension. However, when you type the name of a DOS file in conjunction with a DOS utility, you can use upper- or lowercase letters. Because DOS does not provide an equivalent to the ``executable'' permission bit, the three letter extension is used to indicate if a file is executable. Files ending in .EXE, .SYS or .COM are programs, and files ending in .BAT are batch (script) files.
If you create a file on a SCO OpenServer system and transfer it to a DOS system, try to avoid giving it one of these extensions. Otherwise, DOS may mistake it for an executable program, with unpredictable results.
When copying files from a DOS disk to a SCO OpenServer system, uppercase filenames are automatically converted to lowercase. When copying files from a SCO OpenServer disk to a DOS disk, lowercase names are truncated to fit the DOS filename convention and converted to uppercase.
See doscmd(C) for more details of DOS filenaming conventions.